Lithium battery materials industry: the road twists and turns a bright future
Speaking note of the meeting
Small lithium battery industry in the 1990s are now at a mature stage. Lithium battery research since the 1970s, but until the 1990s, security remains unresolved, mainly due to the use of lithium metal anode material, easy to explode. SONY as a company until the carbon anode materials, the safety issues have been resolved, since the lithium batteries in computers, mobile phones, digital cameras and other areas to be universal.
Traditional energy sources are depleting, power lithium gotten greater attention, the rapid development of the field of cathode materials. Small lithium and lithium cobalt oxide used as the anode and cathode carbon materials, but if the application of new energy vehicles, the following problems: First, as a scarce resource of cobalt, high cost; second car in the process of acceleration and deceleration to bring high-current charge and discharge , deposition of lithium in the anode, thereby supporting grain production, through film, causing the battery short circuit, high-calorie organic electrolyte under the conditions in the explosion. From the 1990s, the United States invented the Goodenough professor of lithium iron phosphate, the material rate performance, high current density does not change the structure, allowing lithium battery in the power of applications possible. Lithium iron phosphate, but there are many problems need to be resolved: low voltage (3.3V, lithium cobalt oxide is 3.7V), low energy density.
Although the defective power lithium present, but the problem can be resolved in the development of the industry next great career. Battery as a system, although the cathode material developed rapidly over the past few years, but the diaphragm, electrolyte, cathode, there are many problems to be solved. 1) There are many kinds of lithium battery cathode materials, the most important is carbon, which application is more middle-carbon-dimensional ball, this has been the industrialization of Shenzhen BTR. However, applications in the power needed to solve the large lithium charge-discharge current density the deposition of lithium in the anode material issues; 2) currently meet the small lithium electrolyte applications, but applications in power need to be modified on lithium, flame, etc. research; 3) high-temperature polymer membrane obturator also need to avoid short-circuit and other aspects to be improved. Short term, there are still many problems power lithium, but Should look long term, as technology continues to develop, the industry's future promising future.
Fluoride short-term valuation is reasonable, long-term value remains to be seen lithium hexafluorophosphate progress of the project of aluminum fluoride Fluoride is currently ex-factory price in 7500 yuan / ton, down again last week, a large number of primary and pre-stocking the downstream manufacturers; cryolite remain relatively stable In 6700 yuan / ton, we mentioned in previous reports, this year because of lower operating rate of the aluminum industry and put on some of the new capacity comes on stream, cryolite obvious gap in the short term needs. Inorganic fluoride for 10 years, 1.05 yuan, 1.38 yuan of 11-year forecast, because the first industry to maintain 10% growth, followed by the company with cryolite circulation process routes, and cost advantages of anhydrous aluminum fluoride higher than the industry growth is expected to achieve speed; for lithium hexafluorophosphate is currently conducting equipment installation, according to the Taurus experience, because the lithium hexafluorophosphate special production process, equipment needed for non-standard transformation, the transformation effect to be seen, so the uncertainty is relatively large piece of business.
How to use a nickel-metal hydride battery design of ultra-bright LED lights
A Ni-MH battery voltage is only 1.2V, and 3.3V Ultra Bright LED above the operating voltage required to ensure sufficient brightness. So. Must find ways to increase the voltage, the common boost circuit generally have two forms, namely high-frequency oscillator circuit and electromagnetic inductive boost circuit. For the boost circuit, two circuits to choose from.
Figure 1 circuit uses a small pulse transformer, high frequency oscillation power tube VT3 will signal amplification, the increase in L1 through direct step-up transformer T.
Figure 2 is the use of self-inductance of the inductor to achieve high voltage upgrade. When the oscillation signal input VT3's base when, VT3 will periodically saturated end. When saturated, the inductance L power, electric energy into magnetic energy stored in L, then the diode cut-off, the energy stored by the C3 power to the load; when the deadline VT3. Inductance will result in lower self-induction electromotive force is on the negative. VD diode conduction, the superposition of self-induction electromotive force electromotive force and to charge capacitor C3 and the load, force is due to two strings. Can be even higher than the supply voltage, the specific size of the load and VT3 mainly by the saturation current through the inductor L when the ratio determined.
Both circuits can be increased to 3.3V above 1.2V, the first circuit in the transformer if the positive feedback on the increase around the coil. Oscillation circuit can be removed. Make the circuit more compact. However, the use of this circuit calculations more complicated. Difficult to adjust the output power, the transformer winding also some trouble. The second only a small inductor. Inductance and no large requirements, regulating the inductor current drive, you can easily adjust the output voltage. In this use of the second circuit.
Oscillator circuit shown in Figure 3, although able to work in 1.2V voltage oscillator circuit there are many, but proven, making the circuit of Figure 3 is easy, simple calculation. High success rate. Oscillation frequency is also easy to determine. And. Adjust the size of the R4, you can not affect the signal frequency in the premise of regulating signal range, so use this circuit to generate a high frequency square wave pulse to prepare for the step-up circuit. As a result, the circuit design is completed by Figures 2 and 3 together constitute.
On the circuit parameters, which lies in power. Inductive power, the stored energy is E = LI2 / 2, Let f be a square wave frequency, 1a within the switch will turn f times, so. Inductive energy stored per second is W = f x E, set the load to the energy conversion efficiency n, then the output power P = n x W + Po, Po is the power supply power directly to load (because the power and self-inductance high-voltage overlay must consider this point).
Now be estimated. Drive an LED to about 100mW. Power Po is about 20mW. In order to ensure the supply, calculated according to P = 100mW. Take n = 80%, then just find a few hundred uH inductor, such as the 500 uH: On the other hand, according to the conservation of energy. 1.2V to 3.3V is about 3 times. Then due to efficiency. Inductive drive current to LED current of about 3-4 times, it is taken as 120mA, this way. Can calculate the oscillation frequency of 34kHz or so, so, take R = 2kn, C = 0.01 uF will be able to meet the requirements. Determine the parameters. Can be high not low frequency, inductive rather large not small, so as to ensure the output power is large enough to have enough adjustments.
As the circuit is simple. Components in the 2 x 2cm board. As long as the correct operation, the power circuit can work. Do not connect the first LED, the output voltage is measured with a multimeter, this time, adjust the size of R4, R4 greater the output voltage is smaller. And vice versa, when the output voltage is 3.2V or so, you can connect the LED, and then adjust the size of the R4, it is sufficient light, note that the voltage across the LED can not make more than 3.6V, otherwise it may burn LED. As a result, the circuit will be completed commissioning.
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